Potere Arcano is the the core of a new RPG I'm working on. Right now, the only rules in the game are how to cast spells, how to get better at casting spells and how to do battle with magic. I am planning on adding rules to govern other things, but spellcasting is the central mechanic around which everything will be built.

To those who actually know Italian, I'd like to apologize in advance for the butchering of it I do here to name things.
Potere Arcano (Power of Magic):
Magic is an ancient and hallowed art. By channeling the energy buried deep within the mind, powerful spells can be invoked. To unlock this energy, one must study the ways of the seven types of magic and bend them to your will. The path to power is long and arduous, but one who walks it will find great rewards.

The Domains of Magic:
There are seven Domains of magic. Four of them are Gesto (actions) while the remaining 3 are Tema (targets). Every spell makes use of two domains: one Gesto, defining what the spells does, and one Tema, defining what the spell effects. The greater the caster's knowledge of a Domain, the more powerful their spells in that domain can be.

Each Domain has 3 sub-domains. The three sub-domains together define what the Domain is.

Domain Grado:
As said above, a Mage's knowledge of a Domain grants them the power to use it in magic. This knowledge is measured with a Grado (rank) ranging from 0 to 5; each Mage has a Grado in each of the seven Domains.

A Grado of 0 means the Mage has not yet devoted any study to that Domain at all. Grado 3 is passable skill for a Mage while Grado 5 denotes total mastery of the Domain. Each Grado also comes with a title Mages can use to describe their knowledge of a Domain.

Dono:
Mages can focus their training on more specific types of magic. A Mage can have one Dono (focus) in each domain, choosing one of its sub-domains to specialize in. When casting spells that fit into their Dono, the Mage's Domain is treated as 1 Grado higher.

Mana Well Depth:
Beyond their knowledge of the domains, the most important thing about a Mage is the Depth of their Mana Well, which marks the amount of magical energy they can safely hold at once.

There are two types of magical energy: Fonte (source) and Scarto (waste). Fonte is pure magic energy that powers spells cleanly; Scarto is waste magical energy created by casting spells without Fonte. A Mage with too much energy in their Mana Well will find that it makes casting spells more difficult.

At dawn each day, each Mage's Mana Well resets; they lose all Scarto and gain Fonte up to double their Well Grado (i.e. after the reset, their Fonte equals double their Well Grado).

The Depth of a Mage's Mana Well also grants them a title, indicating their rank as a Mage.

Casting Spells:
Mages can try to cast any spell they can think of at any time. Each spell cast requires a Spell Check.

To make a Spell Check, add together the caster's Grado in the two Domains that make up the spell, then flip four coins. Every coin that lands heads adds one to the Domain total; every coin that lands tails subtracts one from the Domain total. Finally, subtract 1 from the total for each Scarto the caster has.

If the total is at least the Level of the spell, the spell works; if not, it fails and nothing happens. The Level of a spell is based on its effects, as follows.

Mana Costs:
Casting spells requires the use of magical energy. The caster must pay one Fonte; if they can't, they instead gain one Scarto. Pay the cost before making the Spell Check. However, if their Domain total is at least 4 above the Level of the spell, they get a refund, undoing the cost (gaining one Fonte or losing one Scarto, as appropriate).

Determining a Spells Level:
The power of a spell is measured by its Level. Determining the Level of a spell requires determining its Base Level, then adding modifiers based on things like range and duration.

Base Spell Level:
The base level of a spell is based on how hard it would be to create the spell's effect without magic. Each base level has a special name as well.

Simple spells (Level 1):
Simple spells can do things that an unskilled person can do, such as moving things around, or that would occur naturally, like minor wounds healing. Simple spells can also modify or enhance capabilities the target already has.

Advanced spells (Level 2):
Advanced spells can do things that could be done by a trained or skilled person, such as building things, or things that could happen albeit rarely, such as someone getting struck by lightning.

Elite spells (Level 3):
Elite spells can do things that a normal plant or animal could do, such as flying or breathing underwater. Creating plants and animals out of thin air also falls under this level.

Pure spells (Level 4):
Pure spells can do things that are otherwise impossible, such as creating objects out of thin air or ending spells.

Other Factors:
Other factors can increase the level of the spell. When casting the spell, the Mage chooses the factors they want, adding together any Level increases and adding them to the Base Level.

Range:
By default, spells target either the Mage or a thing they are touching.
-- Level +1: It can target anything within 100 feet of the Mage.
-- Level +2: It can target anything the Mage can see.
-- Level +3: It can target anything the Mage has ever touched.

Duration:
By default, spells either happen instantly or last for 3 minutes after being cast.
-- Level +1: The spell lasts 12 hours.
-- Level +2: The spell lasts 7 days.
Created objects vanish when the spell ends; Level +3 makes them last forever instead.

Target:
By default, spells target one thing; one person, one sword, etc.
-- Level +1: The spell targets just a part of a thing.
-- Level +2: The spell targets a small group of things.

Casting Time:
By default, casting a spell takes 10 seconds.
-- Level +1: The spell takes 2 seconds to cast.
-- Level +2: The spell takes a tenth of a second to cast.
-- Level -1: The spell takes 10 minutes to cast.
10 minute spells are also known as Rituals and also require the use of a spell circle.

Components:
By default, spells require the use of both magic words and gestures.
-- Level +1: The spell requires either magic words or gestures, but not both.

Time Saved:
Magic often does things faster than normal. If the spell only saves minutes or hours, the level is unaffected.
-- Level +1: The spell saves Days or Weeks.
-- Level +2: The spell saves Months.

Spell Mastery:
Mages can study specific spells to Master them, making them easier to cast. If a Mage has Mastered a Spell, they add +2 to their Spell Check total when casting it. When casting a Mastered spell, they can't change any factor of that spell; in effect, all they do is aim the spell.

Limits of Magic:
As powerful as magic is, it suffers from two major Limits: it can not affect Souls or Time in any way. It simply can't be done. The dead shall remain dead and the past shall remain the past.

Mage's Shield:
There is one other limit magic suffers from: the Mage's Shield. Mages are naturally protected from magic. Under normal circumstances, a Mage can only be effected by a spell if they want to be.

Myths:
Myths are various mystical creatures, holding powerful magic. For example, angels, dragons, demons and hydra are all types of Myths. Myths are capable of casting spells within their field of influence and of extreme physical feats.

Each Myth has control over a single Tema Dono. They can cast any spell that fit into that Dono. All Myths also have physical strengths and abilities far outstripping mortals and can use them to do things that mortals would require spells for.

Each Myth has two Sfera (spheres) of power. They are as follows:
-- Magicia (magical): Casting spells in their Tema Dono.
-- Mitico (mythic): Mythic physical abilities.

Each Sfera is ranked on a scale of 3 to 9, showing how much power the Myth has in it. Each Grado has both a name and label.

When a Myth is trying to use their powers, treat it like casting a spell; they use their matching Sfera Grado instead of Domains (which they lack). Myths have the same Mage's Shield that mages do; inversely, the Mage's Shield is capable of protecting from Myths, no matter which Sfera the Myth uses.

Mage Duels:
Mages often find themselves facing off against another Mage or a Myth. In such cases, they take part in a Duel. A Duel takes place over two rounds. In each round, both Mages choose a spell for the fight and Make a Spell Check. The level of the spell doesn't matter in a duel; instead, the Mage with the higher total wins the round.

The winner of the first round takes Advantage, adding +2 to their Spell Check total in the second round. If their total was 4 or more higher than their opponent, they Crush their opponent and win the Duel instantly (skip the second round). If the first round is tied, no one has Advantage in the second round.

The winner of the second round wins the Duel. If the second round is tied, the winner is random; flip a coin. The spell a Mage uses in the second round must not share any Domains with the spell they used in the first round; Myths must use their other Sfera in the second round.

The winner of the duel may cast a single spell (or mythic feat) upon their opponent, ignoring their opponent's Mage's Shield when doing this.

Training and Study:
Mages grow stronger through study. Time spent studying is counted in three month Study Periods. Each period a Mage spends studying gives them 1 Study Point. They don't need to be studying every moment of that time; they must study for at least 8 hours a day and can miss up to 12 days of study in the period. SP is spent to learn more about magic:

-- Increasing a Domain's Grado costs SP equal to the Grado it will become.
-- Learning a new Dono costs SP equal to the number of Dono the Mage will have.
-- Mastering a new spell costs 1 SP.

General knowledge is needed before a Mage can go too deep into any Domain; a Mage's highest Domain can not be more than 3 Grado above their lowest Domain.

SP must be spent immediately when earned; they are "assigned" to a cost and give the benefit when the full cost is met.

Libretto:
Mages who want to learn faster will find what they need in Libretto (Tomes). Each Libretto is about one Domain.

Using a Libretto during a study period allows the knowledge and magic in the Libretto to give the reader an extra SP which must be spent on raising the Domain the Libretto is about. Each Mage can only use each Libretto once and can not use one they wrote.

It takes six months to write a Libretto. When writing a Libretto, they writer chooses its Domain; they must be at least an Expert (Grado 3) in that Domain. Mages can't gain any SP while writing a Libretto.

Teaching:
Mages can learn from those who came before them. A Mage can Teach up to 3 students per study period; each of those students gets an extra SP that period. The teacher can't study or be taught during that study period; they can however use a Libretto to get the extra SP from that.

Any Mage can Teach, but not everyone can Teach well. SP gained from teachers on raising Domains where the teacher's Grado is higher than the students or on gaining Dono the teacher already has.

Digging the Well:
By spending time practicing instead of studying, Mages can deepen their Mana Well. It takes study periods of practice equal the Well Grado they will have to increase their Well Grado by 1. Mages can't study, teach, write or use a Libretto while practicing; they can however be taught to get the extra SP from that.

Practice is useless without knowledge to back it up. A Mage's Well Grado can never be higher than their highest Domain Grado.

Graduation:
Mages spend four years in school learning the basics of magic. The first two years are spent teaching them how the world works and getting them ready to have their Mana Well pulled open. At the end of those two years, they are a Novice (Grado 0) in all 7 Domains and an Initiate (Well Grado 1) overall.

The next two years are spent studying magic. In those two years, they earn 16 SP; 8 from the eight study periods and 8 from the teachers at the school. At most schools, students can give up 2 of their 16 SP to become a Practitioner (Well Grado 2), replacing two periods of study with practice.